These functions return credential information from an sd_bus_creds
object. Credential objects may be created with
sd_bus_creds_new_from_pid(3), in which case they describe the
credentials of the process identified by the specified PID, with
sd_bus_get_name_creds(3), in which case they describe the credentials
of a bus peer identified by the specified bus name, with
sd_bus_get_owner_creds(3), in which case they describe the
credentials of the creator of a bus, or with
sd_bus_message_get_creds(3), in which case they describe the
credentials of the sender of the message.
Not all credential fields are part of every "sd_bus_creds" object.
Use sd_bus_creds_get_mask(3) to determine the mask of fields
available.
sd_bus_creds_get_pid() will retrieve the PID (process identifier).
Similarly, sd_bus_creds_get_ppid() will retrieve the parent PID. Note
that PID 1 has no parent process, in which case -ENXIO is returned.
sd_bus_creds_get_tid() will retrieve the TID (thread identifier).
sd_bus_creds_get_uid() will retrieve the numeric UID (user
identifier). Similarly, sd_bus_creds_get_euid() returns the effective
UID, sd_bus_creds_get_suid() the saved UID and
sd_bus_creds_get_fsuid() the file system UID.
sd_bus_creds_get_gid() will retrieve the numeric GID (group
identifier). Similarly, sd_bus_creds_get_egid() returns the effective
GID, sd_bus_creds_get_sgid() the saved GID and
sd_bus_creds_get_fsgid() the file system GID.
sd_bus_creds_get_supplementary_gids() will retrieve the supplementary
GIDs list.
sd_bus_creds_get_comm() will retrieve the comm field (truncated name
of the executable, as stored in /proc/pid/comm).
sd_bus_creds_get_tid_comm() will retrieve the comm field of the
thread (as stored in /proc/pid/task/tid/comm).
sd_bus_creds_get_exe() will retrieve the path to the program
executable (as stored in the /proc/pid/exe link, but with the "
(deleted)" suffix removed). Note that kernel threads do not have an
executable path, in which case -ENXIO is returned.
sd_bus_creds_get_cmdline() will retrieve an array of command line
arguments (as stored in /proc/pid/cmdline). Note that kernel threads
do not have a command line, in which case -ENXIO is returned.
sd_bus_creds_get_cgroup() will retrieve the control group path. See
cgroups.txt[1].
sd_bus_creds_get_unit() will retrieve the systemd unit name (in the
system instance of systemd) that the process is a part of. See
systemd.unit(5). For processes that are not part of a unit, returns
-ENXIO.
sd_bus_creds_get_user_unit() will retrieve the systemd unit name (in
the user instance of systemd) that the process is a part of. See
systemd.unit(5). For processes that are not part of a user unit,
returns -ENXIO.
sd_bus_creds_get_slice() will retrieve the systemd slice (a unit in
the system instance of systemd) that the process is a part of. See
systemd.slice(5). Similarly, sd_bus_creds_get_user_slice() retrieves
the systemd slice of the process, in the user instance of systemd.
sd_bus_creds_get_session() will retrieve the identifier of the login
session that the process is a part of. See systemd-logind.service(8).
For processes that are not part of a session, returns -ENXIO.
sd_bus_creds_get_owner_uid() will retrieve the numeric UID (user
identifier) of the user who owns the login session that the process
is a part of. See systemd-logind.service(8). For processes that are
not part of a session, returns -ENXIO.
sd_bus_creds_has_effective_cap() will check whether the capability
specified by capability was set in the effective capabilities mask. A
positive return value means that it was set, zero means that it was
not set, and a negative return value indicates an error. See
capabilities(7) and the AmbientCapabilities= and
CapabilityBoundingSet= settings in systemd.exec(5).
sd_bus_creds_has_permitted_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the permitted
capabilities mask.
sd_bus_creds_has_inheritable_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the inheritable
capabilities mask.
sd_bus_creds_has_bounding_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the bounding
capabilities mask.
sd_bus_creds_get_selinux_context() will retrieve the SELinux security
context (label) of the process.
sd_bus_creds_get_audit_session_id() will retrieve the audit session
identifier of the process. Returns -ENXIO for processes that are not
part of an audit session.
sd_bus_creds_get_audit_login_uid() will retrieve the audit user login
identifier (the identifier of the user who is "responsible" for the
session). Returns -ENXIO for processes that are not part of an audit
session.
sd_bus_creds_get_tty() will retrieve the controlling TTY, without the
prefixing "/dev/". Returns -ENXIO for processes that have no
controlling TTY.
sd_bus_creds_get_unique_name() will retrieve the D-Bus unique name.
See The D-Bus specification[2].
sd_bus_creds_get_well_known_names() will retrieve the set of D-Bus
well-known names. See The D-Bus specification[2].
sd_bus_creds_get_description() will retrieve a descriptive name of
the bus connection of the peer. This name is useful to discern
multiple bus connections by the same peer, and may be altered by the
peer with the sd_bus_set_description(3) call.
All functions that take a const char** parameter will store the
answer there as an address of a NUL-terminated string. It will be
valid as long as c remains valid, and should not be freed or modified
by the caller.
All functions that take a char*** parameter will store the answer
there as an address of an array of strings. Each individual string is
NUL-terminated, and the array is NULL-terminated as a whole. It will
be valid as long as c remains valid, and should not be freed or
modified by the caller.

Returned errors may indicate the following problems:
-ENODATA
The given field is not available in the credentials object c.
-ENXIO
The given field is not specified for the described process or
peer. This will be returned by sd_bus_get_unit(),
sd_bus_get_slice(), sd_bus_get_user_unit(),
sd_bus_get_user_slice(), sd_bus_get_session(), and
sd_bus_get_owner_uid() if the process is not part of a systemd
system unit, systemd user unit, systemd slice, or logind session.
It will also be returned by sd_bus_creds_get_exe() and
sd_bus_creds_get_cmdline() for kernel threads (since these are
not started from an executable binary, nor have a command line),
and by sd_bus_creds_get_audit_session_id() and
sd_bus_creds_get_audit_login_uid() when the process is not part
of an audit session, and sd_bus_creds_get_tty() if the process
has no controlling TTY.
-EINVAL
Specified pointer parameter is NULL.
-ENOMEM
Memory allocation failed.

This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2019-05-09. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2019-05-09.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
systemd 234 SD_BUS_CREDS_GET_PID(3)